US4048520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three-phase SCR drive circuit using an opto-coupled pulse amplifier
Assignee: Westinghouse Electric Corp
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Filing: 1976-05-24
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Granted: 1977-09-13
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Expires: 1996-05-24
Abstract
Abstract A three-phase shift network includes a single transistor which controls phase shift by introducing a variable resistance into the network as determined by a D.C. control signal supplied to the transistor. The three-phase signals generated from the phase shift network undergo pulse shaping and are subsequently introduced into an opto-coupled pulse amplifier. The amplifier drives large SCR devices, connected as a load.
Inventors
- 👤 Nicholas G. Muskovac
- 👤 Bruce I. Formhals
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:27
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/08; H02M1/084; Y; Y10; Y10S; Y10S323/00; Y10S323/902
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
103 words
An SCR drive circuit comprising: a plurality of means for selectively shifting each phase of multiple phase electrical signals; respective means each having an output and connected in circuit with an output of each phase shifting means for shaping each of the phase shifted signals; and respective opto-coupled means connected in circuit with an output of a respective shaping means for generating trigger signals for firing SCR devices connected as loads to respective opto-coupled means; respective means connected between an input of each phase shifting means and power lines for isolating the respective phase shifting means from direct connection to the power lines.
Claim 2
Dependent Claim
103 words
An SCR drive circuit comprising: a plurality of means for selectively shifting each phase of multiple phase electrical signals; respective means each having an output and connected in circuit with an output of each phase shifting means for shaping each of the phase shifted signals; and respective opto-coupled means connected in circuit with an output of a respective shaping means for generating trigger signals for firing SCR devices connected as loads to respective opto-coupled means; respective means connected between an input of each phase shifting means and power lines for isolating the respective phase shifting means from direct connection to the power lines.
Claim 3
Dependent Claim
56 words
The subject matter set forth in claim 1 wherein each phase shifting means includes an individual diode rectifier bridge for full wave rectification of a particular phase signal present at an input of the bridge; and a single variable resistive means connected to the bridges associated with all phases for controlling the amount of phase shift.
Claim 4
Dependent Claim
18 words
The subject matter set forth in claim 1 wherein the isolating means is a multiple phase isolation transformer.
Claim 5
Dependent Claim
22 words
The subject matter set forth in claim 2 wherein the variable resistive means is a transistor operating in a Class "A" mode.
Claim 6
Dependent Claim
29 words
The subject matter set forth in claim 4 together with variable D.C. bias means connected to the transistor for controlling the resistivity which the transistor introduces to the bridges.
Claim 7
Dependent Claim
104 words
A phase shifting network for multiple phase operation comprising: a plurality of rectifier diode bridges, each bridge having: first and second terminals connected to a source of A.C. power; third and fourth terminals respectively connected to an emitter and a collector of a common transistor; means for introducing a variable D.C. bias to a base of the transistor for varying the resistivity imposed by the transistor on all of the bridges; and connecting means connected to the second terminal and a preselected potential point of the power source for making available thereat a signal that is phase shifted relative to the remaining diode bridges.
Claim 8
Dependent Claim
104 words
A phase shifting network for multiple phase operation comprising: a plurality of rectifier diode bridges, each bridge having: first and second terminals connected to a source of A.C. power; third and fourth terminals respectively connected to an emitter and a collector of a common transistor; means for introducing a variable D.C. bias to a base of the transistor for varying the resistivity imposed by the transistor on all of the bridges; and connecting means connected to the second terminal and a preselected potential point of the power source for making available thereat a signal that is phase shifted relative to the remaining diode bridges.
References Cited (Backward Citations)
US3524986A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |